Noise reduction method and apparatus, and mobile terminal

Abstract

Embodiments of the present disclosure provide a noise reduction method, the method includes: obtaining an acceleration signal of a mobile terminal when an audio output device is in a working state; determining, according to the acceleration signal, a vibration waveform of the mobile terminal when the mobile terminal vibrates; inverting the determined vibration waveform to obtain a noise reduction signal; and superimposing the noise reduction signal onto to-be-output audio of the audio output device. Therefore, noise generated by skeleton vibration is diminished or eliminated, so as to improve an effect of listening, by a person, to audio.

What is claimed is: 
     
       1. A mobile terminal comprising:
 a processor; 
 an audio output device configured to output audio; 
 a sensor configured to generate an acceleration signal of the mobile terminal; 
 a noise reduction signal determining circuit configured to:
 obtain the acceleration signal of the mobile terminal when the audio output device is in a working state, 
 integrate the acceleration signal to generate a rate signal, 
 calculate a shift signal based on the rate signal to obtain a vibration waveform of the mobile terminal when the mobile terminal vibrates, and 
 invert the vibration waveform to obtain a noise reduction signal; and 
 
 a coupling circuit configured to superimpose the noise reduction signal onto to-be-output audio of the audio output device. 
 
     
     
       2. The mobile terminal according to  claim 1 , wherein the noise reduction signal determining circuit comprises:
 a first integrator circuit configured to integrate the acceleration signal to generate the rate signal; and 
 a second integrator circuit configured to integrate the rate signal to generate the vibration waveform of the mobile terminal. 
 
     
     
       3. The mobile terminal according to  claim 2 , wherein the first integrator circuit comprises a resistor R 1 , a resistor R 2 , a capacitor C 1 , a capacitor C 2 , and an operational amplifier U 1 ,
 wherein a first end of the resistor R 1  receives the acceleration signal, a second end of the resistor R 1  is electrically connected to an in-phase input end of the operational amplifier U 1  and a first end of the capacitor C 1  separately, and a second end of the capacitor C 1  is grounded, and 
 wherein a first end of the resistor R 2  is grounded, a second end of the resistor R 2  is electrically connected to a reverse-phase input end of the operational amplifier U 1  and a first end of the capacitor C 2  separately, and an output end of the operational amplifier U 1  outputs the rate signal. 
 
     
     
       4. The mobile terminal according to  claim 3 , wherein the second integrator circuit comprises a resistor R 3 , a resistor R 4 , a capacitor C 3 , and an operational amplifier U 2 ,
 wherein the output end of the operational amplifier U 1  is electrically connected to a first end of the resistor R 3  and a second end of the capacitor C 2  separately, and 
 wherein a second end of the resistor R 3  is electrically connected to a reverse-phase input end of the operational amplifier U 2  and a first end of the capacitor C 3  separately, a first end of the resistor R 4  is grounded, a second end of the resistor R 4  is electrically connected to an in-phase input end of the operational amplifier U 2 , and an output end of the operational amplifier U 2  is connected to a second end of the capacitor C 3 . 
 
     
     
       5. The mobile terminal according to  claim 2 , further comprising:
 a phase-shift circuit configured to shift forward or shift backward a phase of the determined vibration waveform. 
 
     
     
       6. The mobile terminal according to  claim 4 , further comprising:
 a phase-shift circuit configured to shift forward or shift backward the vibration waveform, 
 wherein the phase-shift circuit comprises a resistor R 5  and a capacitor C 4 , 
 wherein the output end of the operational amplifier U 1  is electrically connected to the first end of the resistor R 3  by using the resistor R 5 , and 
 wherein a first end of the resistor R 5  is electrically connected to the output end of the operational amplifier U 1  and the second end of the capacitor C 2  separately, a second end of the resistor R 5  is electrically connected to the first end of the resistor R 3 , a first end of the capacitor C 4  is grounded, and a second end of the capacitor C 4  is connected between the resistor R 5  and the resistor R 3 . 
 
     
     
       7. The mobile terminal according to  claim 6 , wherein the coupling circuit comprises a capacitor C 5 , and
 wherein a first end of the capacitor C 5  is electrically connected to the output end of the operational amplifier U 2  and the second end of the capacitor C 3  separately, and a second end of the capacitor C 5  is connected to the audio output device. 
 
     
     
       8. A mobile terminal comprising:
 a sensor configured to generate an acceleration signal of the mobile terminal; 
 an audio output device configured to output audio; 
 a memory configured to store software instructions; and 
 a processor configured to execute the software instructions to:
 obtain the acceleration signal of the mobile terminal when the audio output device is in a working state; 
 integrate the acceleration signal to generate a rate signal; 
 calculate a shift signal based on the rate signal to obtain a vibration waveform of the mobile terminal when the mobile terminal vibrates; 
 invert the vibration waveform to obtain a noise reduction signal; and 
 superimpose the noise reduction signal onto to-be-output audio of the audio output device. 
 
 
     
     
       9. The mobile terminal according to  claim 8 , wherein the processor is further configured to:
 shift forward or shift backward the determined vibration waveform by a phase. 
 
     
     
       10. The mobile terminal according to  claim 8 , wherein the processor is further configured to:
 adjust the acceleration signal to make an amplitude of the adjusted acceleration signal fall within a predetermined amplitude range; and 
 determine, based on the adjusted acceleration signal, the vibration waveform of the mobile terminal when the mobile terminal vibrates. 
 
     
     
       11. A noise reduction method, applicable to a mobile terminal, which is provided with an audio output device configured to output audio, wherein the method comprises:
 generating an acceleration signal of the mobile terminal when the audio output device is in a working state; 
 integrating the acceleration signal to generate a rate signal; 
 calculating a shift signal based on the rate signal to obtain a vibration waveform of the mobile terminal when the mobile terminal vibrates; 
 inverting the vibration waveform to obtain a noise reduction signal; and 
 superimposing the noise reduction signal onto to-be-output audio of the audio output device. 
 
     
     
       12. The method according to  claim 11 , wherein before inverting the determined vibration waveform, the method further comprises:
 shifting forward or shifting backward the determined vibration waveform by a phase. 
 
     
     
       13. The method according to  claim 11 , wherein before determining the vibration waveform of the mobile terminal when the mobile terminal vibrates, the method further comprises:
 adjusting the acceleration signal to make an amplitude of the adjusted acceleration signal fall within a predetermined amplitude range.